Cancer and infectious disease are significant health problems throughout the world. Although advances have been made in detection and therapy of these diseases, no vaccine or other universally successful method for prevention or treatment is currently available. Current therapies, which are generally based on a combination of chemotherapy or surgery and radiation, continue to prove inadequate in many patients.
For example, primary breast carcinomas can often be treated effectively by surgical excision. If further disease recurs, however, additional treatment options are limited, and there are no effective means of treating systemic disease. While immune responses to autologous tumors have been observed, they have been ineffective in controlling the disease. One effort to stimulate a further anti-tumor response is directed at the identification of tumor antigens useful for vaccines. A related approach takes advantage of the promiscuous peptide binding properties of heat shock proteins, such as hsp70. These molecular chaperones bind peptides and are involved in numerous protein folding, transport and assembly processes, and could be involved in the antigen presentation pathway of MHC complexes.
The heat shock proteins of mammalian cells can be classified into several families of sequence related proteins. The principal mammalian hsps, based on protein expression levels, are cytoplasmic/nuclear proteins with masses of (approximately) 25 kDa (hsp25), 70 kDa (hsp70), 90 kDa (hsp90), and 110 kDa (hsp110). However, in addition to hsps, a second set of stress proteins is localized in the endoplasmic reticulum (ER). The induction of these stress proteins is not readily responsive to hyperthermic stress, as are the hsps, but are regulated by stresses that disrupt the function of the ER (e.g. glucose starvation and inhibitors of glycosylation, anoxia and reducing conditions, or certain agents that disrupt calcium homeostasis). These stress proteins are referred to as glucose regulated proteins (grps). The principal grps, on the basis of expression, have approximate sizes of 78 kDa (grp78), 94 kDa (grp94), and 170 kDa (grp170). Grp78 is homologous to cytoplasmic hsp70, while grp94 is homologous to hsp90.
While individual stress proteins have been studied for several years (in some cases intensively studied, e.g. hsp70), the largest of the above hsp and grp groups, hsp110 and grp170, have received little attention. Both have been found by sequence analysis to represent large and highly diverged relatives of the hsp70 family. It is recognized that the hsp70 family, the hsp110 family, and the grp170 family comprise three distinguishable stress protein groups of eukaryotic cells that share a common evolutionary ancestor. The existence of hsp110 in parallel with hsp70 in the cytoplasm and of grp170 in parallel with grp78 in the ER of (apparently) all eukaryotic cells argues for important differential functions for these distantly related protein families. Not all stress proteins function as vaccines, however, and it can be expected that different ones may exhibit different activities.
In spite of considerable research into therapies for infectious disease and cancer, these diseases remain difficult to diagnose and treat effectively. Accordingly, there is a need in the art for improved methods for treating cancer and infectious disease. The present invention fulfills these needs and further provides other related advantages.